The Cotley River is a small river in Taunton and Berkley, Massachusetts that is a tributary of the Taunton River. It flows approximately 5.8 miles (9.2 km) in a northwesterly direction from the southeast part of Taunton near Seekell Street to Barstows Pond near the village of East Taunton where it joins the Taunton River.^[1]

The river is crossed twice in Berkley by Allen Frederick's active railroad line that was originally built as the Taunton and New Bedford Railroad in 1840.^[2] It is now operated by CSX.